3da1cf1e88
there is an environment variable which shall initialize the SYSCTL during early boot. This works for all SYSCTL types both statically and dynamically created ones, except for the SYSCTL NODE type and SYSCTLs which belong to VNETs. A new flag, CTLFLAG_NOFETCH, has been added to be used in the case a tunable sysctl has a custom initialisation function allowing the sysctl to still be marked as a tunable. The kernel SYSCTL API is mostly the same, with a few exceptions for some special operations like iterating childrens of a static/extern SYSCTL node. This operation should probably be made into a factored out common macro, hence some device drivers use this. The reason for changing the SYSCTL API was the need for a SYSCTL parent OID pointer and not only the SYSCTL parent OID list pointer in order to quickly generate the sysctl path. The motivation behind this patch is to avoid parameter loading cludges inside the OFED driver subsystem. Instead of adding special code to the OFED driver subsystem to post-load tunables into dynamically created sysctls, we generalize this in the kernel. Other changes: - Corrected a possibly incorrect sysctl name from "hw.cbb.intr_mask" to "hw.pcic.intr_mask". - Removed redundant TUNABLE statements throughout the kernel. - Some minor code rewrites in connection to removing not needed TUNABLE statements. - Added a missing SYSCTL_DECL(). - Wrapped two very long lines. - Avoid malloc()/free() inside sysctl string handling, in case it is called to initialize a sysctl from a tunable, hence malloc()/free() is not ready when sysctls from the sysctl dataset are registered. - Bumped FreeBSD version to indicate SYSCTL API change. MFC after: 2 weeks Sponsored by: Mellanox Technologies
163 lines
4.7 KiB
C
163 lines
4.7 KiB
C
/*-
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* Copyright (c) 1994 John Dyson
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* Copyright (c) 2001 Matt Dillon
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*
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* All Rights Reserved.
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* Redistribution and use in source and binary forms, with or without
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* modification, are permitted provided that the following conditions
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* are met:
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* 1. Redistributions of source code must retain the above copyright
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* notice, this list of conditions and the following disclaimer.
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* 2. Redistributions in binary form must reproduce the above copyright
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* notice, this list of conditions and the following disclaimer in the
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* documentation and/or other materials provided with the distribution.
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* 4. Neither the name of the University nor the names of its contributors
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* may be used to endorse or promote products derived from this software
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* without specific prior written permission.
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*
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* THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS
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* OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED
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* WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE
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* ARE DISCLAIMED. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
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* DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL
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* DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE
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* GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS
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* INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY,
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* WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING
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* NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
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* SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
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*
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* from: @(#)vm_machdep.c 7.3 (Berkeley) 5/13/91
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* Utah $Hdr: vm_machdep.c 1.16.1.1 89/06/23$
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* from: FreeBSD: .../i386/vm_machdep.c,v 1.165 2001/07/04 23:27:04 dillon
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*/
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#include <sys/cdefs.h>
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__FBSDID("$FreeBSD$");
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#include <opt_sched.h>
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#include <sys/param.h>
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#include <sys/systm.h>
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#include <sys/kernel.h>
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#include <sys/proc.h>
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#include <sys/vmmeter.h>
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#include <sys/lock.h>
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#include <sys/mutex.h>
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#include <sys/sched.h>
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#include <sys/sysctl.h>
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#include <sys/kthread.h>
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#include <sys/unistd.h>
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#include <vm/vm.h>
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#include <vm/vm_param.h>
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#include <vm/vm_page.h>
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#include <vm/vm_phys.h>
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static int idlezero_enable_default = 0;
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/* Defer setting the enable flag until the kthread is running. */
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static int idlezero_enable = 0;
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SYSCTL_INT(_vm, OID_AUTO, idlezero_enable, CTLFLAG_RWTUN, &idlezero_enable, 0,
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"Allow the kernel to use idle cpu cycles to zero-out pages");
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/*
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* Implement the pre-zeroed page mechanism.
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*/
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#define ZIDLE_LO(v) ((v) * 2 / 3)
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#define ZIDLE_HI(v) ((v) * 4 / 5)
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static boolean_t wakeup_needed = FALSE;
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static int zero_state;
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static int
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vm_page_zero_check(void)
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{
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if (!idlezero_enable)
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return (0);
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/*
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* Attempt to maintain approximately 1/2 of our free pages in a
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* PG_ZERO'd state. Add some hysteresis to (attempt to) avoid
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* generally zeroing a page when the system is near steady-state.
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* Otherwise we might get 'flutter' during disk I/O / IPC or
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* fast sleeps. We also do not want to be continuously zeroing
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* pages because doing so may flush our L1 and L2 caches too much.
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*/
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if (zero_state && vm_page_zero_count >= ZIDLE_LO(vm_cnt.v_free_count))
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return (0);
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if (vm_page_zero_count >= ZIDLE_HI(vm_cnt.v_free_count))
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return (0);
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return (1);
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}
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static void
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vm_page_zero_idle(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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zero_state = 0;
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if (vm_phys_zero_pages_idle()) {
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if (vm_page_zero_count >= ZIDLE_HI(vm_cnt.v_free_count))
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zero_state = 1;
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}
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}
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/* Called by vm_page_free to hint that a new page is available. */
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void
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vm_page_zero_idle_wakeup(void)
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{
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mtx_assert(&vm_page_queue_free_mtx, MA_OWNED);
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if (wakeup_needed && vm_page_zero_check()) {
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wakeup_needed = FALSE;
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wakeup(&zero_state);
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}
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}
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static void
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vm_pagezero(void __unused *arg)
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{
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idlezero_enable = idlezero_enable_default;
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mtx_lock(&vm_page_queue_free_mtx);
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for (;;) {
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if (vm_page_zero_check()) {
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vm_page_zero_idle();
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#ifndef PREEMPTION
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if (sched_runnable()) {
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thread_lock(curthread);
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mi_switch(SW_VOL | SWT_IDLE, NULL);
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thread_unlock(curthread);
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}
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#endif
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} else {
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wakeup_needed = TRUE;
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msleep(&zero_state, &vm_page_queue_free_mtx, 0,
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"pgzero", hz * 300);
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}
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}
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}
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static void
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pagezero_start(void __unused *arg)
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{
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int error;
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struct proc *p;
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struct thread *td;
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error = kproc_create(vm_pagezero, NULL, &p, RFSTOPPED, 0, "pagezero");
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if (error)
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panic("pagezero_start: error %d\n", error);
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td = FIRST_THREAD_IN_PROC(p);
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thread_lock(td);
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/* We're an idle task, don't count us in the load. */
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td->td_flags |= TDF_NOLOAD;
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sched_class(td, PRI_IDLE);
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sched_prio(td, PRI_MAX_IDLE);
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sched_add(td, SRQ_BORING);
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thread_unlock(td);
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}
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SYSINIT(pagezero, SI_SUB_KTHREAD_VM, SI_ORDER_ANY, pagezero_start, NULL);
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